This specification relates to methods of repairing spinal disc anulus fibrosus and apparatuses for practicing the methods.
The intervertebral disc, lying between adjacent vertebrae in the spine, is a vital structure of highly specialized and organized deformable cartilage, without which the spine would be incapable of supporting loads or maintaining flexibility. In a healthy intervertebral disc, the nucleus pulposus (NP) in the central portion is capable of sustaining and transmitting loads while the outer anulus fibrosus (AF) surrounding the nucleus provides both resistances to stresses and movements of the spine.
Defects of the AF (e.g., circumferential delamination and radial fissures) can result in extrusion of otherwise contained NP tissue, known as spinal disc herniation. Particularly in the posterior region, disc protrusions or fragments of NP can cause pain as they displace the nerve root exiting from the dural sac. Among various methods of treating the herniated intervertebral discs, discectomy (i.e., nucleus removal) is generally considered as a standard of care today. It has been reported that surgically repairing defects in the AF in conjunction with and at the conclusion of discectomy may enhance both the technical and clinical outcomes after these procedures. See, e.g., Yasargil, Adv. Neurosurg. (1977), 4:81, and Cauthen, Spinal Arthoplasty: A New Era in Spine Care (2005), 157-177.
In the past, surgeons have considered and tried suturing the anulus closed using standard sutures, needles, and microsurgical techniques. In a posterior approach, exposure limitations during microdiscectomy make standard suturing difficult to perform. There is a need for developing new suturing techniques and apparatuses to repair defects in the anulus fibrosus following microdiscectomy.